Combined cut-out and lightning-arrester



2 Sheets-Sheet 1.

(No Model.)

Patented Apr. 16, 1895.

(No Model.) 2 Sheets-Sheet 2.- M. J. WIGHTMAN. COMBINED GUT-OUT AND LIGHTNING ARRESTER.

Patented Apr. 16, 1895.

\MTNEEISES- f UNITED STATES PATENT OFFICE.

MERLE J. WIGHTMAN, OF SCRANTON, PENNSYLVANIA, ASSIGNOR TO THE THOMSON-HOUSTON ELECTRIC COMPANY, OF SCI-IENECTADY, NEW YORK.

COMBINED CUT-OUT AND LlGHTNlNG-ARRESTER.

SPECIFICATION forming part of Letters Patent No. 537,513, dated April 16, 1895.

Application filed January 9, 1895. Serial No. 534,306. (No model.

T0 on whom it may concern:

Be it known that I, MERLE J. WIGHTMAN, a citizen of the United States, residing at Scranton, county of Lackawanna, State of Pennsylvania, have invented certain new and useful Improvements in a Combined Cut-Out and.

Lightning-Arrester, of which the following is a specification.

My invention relates to apparatus designed for the protection of electrical devices of any kind, and more especially of dynamo-electric machinery, against damage by lightning or by excess of current; and has particular reference to an arrangement designed to so protect electric cars or locomotives, which are particularly liable to injury from this cause. It has been customary to protect such apparatus by means of fuses, and also to use in each car a lightning-arrester of one type or another. These have been more or less efficient in practice, but it is inconvenient and expensive to locate both these devices upon the car, inasmuch as ordinary constructions take up considerable room and must be placed under the car, a space which is already occupied by the motors and other apparatus. It is therefore of great importance to confine their dimensions within as small limits as possible.

It is to combine the two pieces of apparatus just described in one compact and efficient arrangement that I have devised my present invention, which consists briefly in a box havin g located within it an electro-magnet having a single core and two pole-pieces, one upon either side of the core. Above one of the pole-pieces I place a fuse or circuit-interru pter, and above the other I place alightningarrester. Around the magnet-coils and in series with the spark-gap of the lightning-arrester I place a second spark-gap for the purpose of protecting the coils. Between the lightning arrester and the ground I place a non-inductive resistance to limit the flow of current after a discharge. By this means I am enabled to employ a single magnet for both the fuse and lightning-arrester, as pointed out, thereby effecting a very material saving in the construction of the apparatus, both in its weight and in size and in cost.

The accompanying drawings show an embodiment of my invention.

Figure 1 is a plan with the cover thrown back. Fig. 2 is a section upon the line 3-3 of Fig. l,looking in the direction of the arrow. Fig. 3 is a plan view of the magnet core; and Fig. 4- is a diagram of the circuit connections.

Referring by letters and numerals, A is a box of which Bis the cover. This is ordinarily made of wood, but any material may be employed.

C is a sheet of insulating material upon the cover, preferably of some refractory material.

D is a plate of iron in the cover, and E is a hole in the insulution which exposes a portion of the plate D, permitting the pole D of the magnet to make contact with the iron plate or armature D, and thus greatly strengthen the magnetic circuit.

F, F are co-operating parts of a lock securing the cover When in position.

G is the ground terminal by which the discharge passes from the spark-gap to which I have referred, in shunt around the magnetcoil, and from the lightning-arrester terminals L, L. An adjusting screw with a locknut is provided for the purpose of keeping the points of the spark-gap H at a proper distance apart.

I, I are the terminals of the circuit-breaking arrangement or fuse t'.

K, K are chutes of' insulating material, preferably refractory in its nature, like the sheet C attached to the cover. The particular form of these chutes is not, however, of my invention.

L, L are the lightning-arrester electrodes, secured in place in the circuit by the clamping pieces Z, Z, which are fastened by screws in any ordinary manner. ,7 These points I preferably make of carbon, and they approach more nearly at one point than elsewhere, so that, under the action of the magnetic field, the are following the discharge will be driven to a more widely separated portion of the electrodes and there broken.

M, M are respectively the motor and line terminals of the arrangement.

N is the non-inductive resistance to which I have referred, in circuitbetween the ground terminal G and one of the terminals L of the lightning-arrester.

At 0 is provided a draft opening for the chute K.

Referring now to Fig. 2, the same parts are ICO shown in section, but in this case the openings supplying the chutes K, K" with air are shown at Q, Q. These openings are covered with wire gauze screens R, R, for the purpose of preventing their obstruction with dust and dirt. At d is shown an insulating wrapping for the core of the magnet, and at 61', shown indotted lines, is a dampening sheath or closed band of copper, in order to insure the stability of the magnetic field for a short time afterthe rupture of the line circuit by the blowing of the fuse.

Referring now to Fig. 3, I illustrate the form of the magnet which I have devised for my improved apparatus, wherein I) is the' central pole about which the winding S, shown in Figs. 2 and 4, is wrapped. D D are the pole-pieces which, as shown best in Fig. 2, respectively underlie the fuset and the lightning-arrester terminals L. D is a common base plate or yoke for the three parts of the magnet which is held in place in the box by the screws P, P.

Referring now to Fig. 4, I show the circuit connections of my improved apparatus. The current entering from the line passes across the terminals 1, I by the fuse a, passing around the coils S of the magnet, goes by the lead 1 to the motor '1, and thence out to ground. This is the ordinary course of the current. In case of a disruptive discharge entering from the line, it will first be shunted around the coils of the magnet S, which by reason of their self-induction impede its progress, will pass across the spark-gap H and thence up the lead 1 to the lightning-arrester terminals L, L, through the non-inductive resistance N and out at ground at G. The line current, however, will pass around the coils of the magnet, which afford to it a less resistance than the spark-gap H, and will continue to pass to the motor. Any current flowing after the lightning discharge across the terminals L, L will be limited by the resistance N, and quickly interrupted by the magnetic field of the pole-piece D underlying the terminals. Similarly, should the current become excessive and the fuse 2' blow, the current will still pass across the terminals I, 1' until the arc is extinguished, and passing around the coil S will energize the magnet and go through the motor to ground. The damping sheath upon the magnet at this time comes into play, so that the magnetism in the pole-pieces D D will be kept up for a time even after the are has been extinguished. In either case the arc is quickly and efticiently extinguished either at the fuse terminals I, I or at the lightningarrester terminals L, L, by the combined action of the magnetic fields of the two pole-pieces co-operating with the plate D in the cover, and by the powerful current of air drawn in through the openings Q, Q, coming in at the bottom of the chute K or through the opening 0 of the chute K and passing out at the front of the apparatus.

The practical operation of my combined fuse box and lightning-arrester has been exceedingly successful, and I have found it compact and comparatively light in weight, taking but a small amount of room on an electric car.

WVhat I claim as new, and desire to secure by Letters Patent of the United States, is

1. In a combined cut-out and lightning-arrester, aline circuit, cut-out terminals therein, separate lightning-arrester terminals, and an .eleetro-magnet in the line circuit, the electromagnet having separate pole-pieces under each set of terminals, the pole-pieces having a common armature substantially as described.

2. In a combined cut-out and lightning-an rester, aline circuit, cut-out terminals therein, lightning-arrester terminals, and means for generating a magnetic field adjacent to each set of terminals, consisting of an electro-magnet in the line circuit, having a central core and a separate pole of the same sign under each pair of terminals.

3. In a combined cut-out and lightning-arrester, a line circuit, cut-out terminals therein, lightning-arrester terminals, and an elcctromagnet in the line circuit having a pole of the same sign under each of the sets of terminals, the two poles provided with a common armature.

4c. In a combined cut-out and lightning-arrester, a line circuit, cut-out terminals therein, lightning-arrester terminals, a connection to ground from one of such terminals including a non-inductive resistance, and an olectromagnet in the line circuit, the electro-magnet having pole-pieces of the same sign under each of the sets of terminals, such pole-pieces having a common armature.

In witness whereof I have hereunto set my hand this 5th day of January, 1895.

MERLE J. WIGIITMAN'.

IVitnesses:

R. E. GLASS, J. L. CHAPMAN. 

